﻿using System;
using System.Xml;
using System.Xml.Serialization;
using System.IO;

namespace Sample.Xml
{
    /* The XmlRootAttribute allows you to set an alternate name 
     (PurchaseOrder) of the XML element, the element namespace; by 
     default, the XmlSerializer uses the class name. The attribute 
     also allows you to set the XML namespace for the element.  Lastly,
     the attribute sets the IsNullable property, which specifies whether 
     the xsi:null attribute appears if the class instance is set to 
     a null reference. */

    [XmlRootAttribute("PurchaseOrder", Namespace = "http://www.cpandl.com",

    IsNullable = false)]
    public class PurchaseOrder
    {
        public Address ShipTo;
        public string OrderDate;
        /* The XmlArrayAttribute changes the XML element name
       from the default of "OrderedItems" to "Items". */

        [XmlArrayAttribute("Items")]
        public OrderedItem[] OrderedItems;
        public decimal SubTotal;
        public decimal ShipCost;
        public decimal TotalCost;
    }

    public class Address
    {
        /* The XmlAttribute instructs the XmlSerializer to serialize the Name
         field as an XML attribute instead of an XML element (the default
         behavior). */

        [XmlAttribute]
        public string Name;
        public string Line1;

        /* Setting the IsNullable property to false instructs the 
         XmlSerializer that the XML attribute will not appear if 
         the City field is set to a null reference. */

        [XmlElementAttribute(IsNullable = false)]
        public string City;
        public string State;
        public string Zip;
    }

    public class OrderedItem
    {
        public string ItemName;
        public string Description;
        public decimal UnitPrice;
        public int Quantity;
        public decimal LineTotal;

        /* Calculate is a custom method that calculates the price per item,
         and stores the value in a field. */

        public void Calculate()
        {
            LineTotal = UnitPrice * Quantity;
        }
    }

    public class TestXmlSerializerSample
    {
        public static void Execute()
        {
            // Read and write purchase orders.

            TestXmlSerializerSample t = new TestXmlSerializerSample();
            t.CreatePO("po.xml");
            t.ReadPO("po.xml");
        }

        private void CreatePO(string filename)
        {
            // Create an instance of the XmlSerializer class;

            // specify the type of object to serialize.

            XmlSerializer serializer =
            new XmlSerializer(typeof(PurchaseOrder));
            TextWriter writer = new StreamWriter(filename);
            PurchaseOrder po = new PurchaseOrder();

            // Create an address to ship and bill to.

            Address billAddress = new Address();
            billAddress.Name = "Teresa Atkinson";
            billAddress.Line1 = "1 Main St.";
            billAddress.City = "AnyTown";
            billAddress.State = "WA";
            billAddress.Zip = "00000";
            // Set ShipTo and BillTo to the same addressee.

            po.ShipTo = billAddress;
            po.OrderDate = System.DateTime.Now.ToLongDateString();

            // Create an OrderedItem object.

            OrderedItem i1 = new OrderedItem();
            i1.ItemName = "Widget S";
            i1.Description = "Small widget";
            i1.UnitPrice = (decimal)5.23;
            i1.Quantity = 3;
            i1.Calculate();

            // Insert the item into the array.

            OrderedItem[] items = { i1 };
            po.OrderedItems = items;
            // Calculate the total cost.

            decimal subTotal = new decimal();
            foreach (OrderedItem oi in items)
            {
                subTotal += oi.LineTotal;
            }
            po.SubTotal = subTotal;
            po.ShipCost = (decimal)12.51;
            po.TotalCost = po.SubTotal + po.ShipCost;
            // Serialize the purchase order, and close the TextWriter.

            serializer.Serialize(writer, po);
            writer.Close();
        }

        protected void ReadPO(string filename)
        {
            // Create an instance of the XmlSerializer class;

            // specify the type of object to be deserialized.

            XmlSerializer serializer = new XmlSerializer(typeof(PurchaseOrder));
            /* If the XML document has been altered with unknown 
          nodes or attributes, handle them with the 
          UnknownNode and UnknownAttribute events.*/

            serializer.UnknownNode += new
            XmlNodeEventHandler(serializer_UnknownNode);
            serializer.UnknownAttribute += new
            XmlAttributeEventHandler(serializer_UnknownAttribute);

            // A FileStream is needed to read the XML document.

            FileStream fs = new FileStream(filename, FileMode.Open);
            // Declare an object variable of the type to be deserialized.

            PurchaseOrder po;
            /* Use the Deserialize method to restore the object's state with
          data from the XML document. */

            po = (PurchaseOrder)serializer.Deserialize(fs);
            // Read the order date.

            Console.WriteLine("OrderDate: " + po.OrderDate);

            // Read the shipping address.

            Address shipTo = po.ShipTo;
            ReadAddress(shipTo, "Ship To:");
            // Read the list of ordered items.

            OrderedItem[] items = po.OrderedItems;
            Console.WriteLine("Items to be shipped:");
            foreach (OrderedItem oi in items)
            {
                Console.WriteLine("\t" +
                oi.ItemName + "\t" +
                oi.Description + "\t" +
                oi.UnitPrice + "\t" +
                oi.Quantity + "\t" +
                oi.LineTotal);
            }
            // Read the subtotal, shipping cost, and total cost.

            Console.WriteLine("\t\t\t\t\t Subtotal\t" + po.SubTotal);
            Console.WriteLine("\t\t\t\t\t Shipping\t" + po.ShipCost);
            Console.WriteLine("\t\t\t\t\t Total\t\t" + po.TotalCost);
        }

        protected void ReadAddress(Address a, string label)
        {
            // Read the fields of the Address object.

            Console.WriteLine(label);
            Console.WriteLine("\t" + a.Name);
            Console.WriteLine("\t" + a.Line1);
            Console.WriteLine("\t" + a.City);
            Console.WriteLine("\t" + a.State);
            Console.WriteLine("\t" + a.Zip);
            Console.WriteLine();
        }

        private void serializer_UnknownNode
        (object sender, XmlNodeEventArgs e)
        {
            Console.WriteLine("Unknown Node:" + e.Name + "\t" + e.Text);
        }

        private void serializer_UnknownAttribute
        (object sender, XmlAttributeEventArgs e)
        {
            System.Xml.XmlAttribute attr = e.Attr;
            Console.WriteLine("Unknown attribute " +
            attr.Name + "='" + attr.Value + "'");
        }
    }
}